The container sterilization equipment includes two heads that irradiate an object to be treated with electron beams and two filament power supplies that supply power to the filaments of the two heads. Each of the filament power supplies for the respective heads has a switch that compares a beam depletion threshold value estimated according to the magnitude of a beam control signal with an actual beam current measured value. When the beam current measured value is not higher than the beam depletion threshold value, it is decided that beams are depleted. This stops power supply to the filament of the beam-depleted head while keeping filament power to other heads.
Thus, in an electron-beam irradiating device with power sharing multiple beam heads, discharge from one head stops only an abnormal head but keeps beams to other heads. This eliminates the need for stopping the operations of all the heads.